300 hectares of U Minh Ha melaleuca forest in decline

U Minh Ha National Park is one of the three critical wetland conservation areas in the Mekong Delta, serving concurrently as the core zone of the Mui Ca Mau World Biosphere Reserve recognized by UNESCO. The park spans a total core area of 8.527 hectares, including over 2.593 hectares dedicated to a melaleuca forest conservation sub-zone on peatland and more than 5.190 hectares designated for the sub-zone for wetland ecosystem restoration and sustainable use.

However, in recent years, U Minh Ha National Park has been facing severe ecosystem degradation. Roughly 300 hectares of melaleuca forest are increasingly depleted, with large-scale tree mortalities and mass blowdowns creating vast clearings right inside the core conservation zone. In certain areas, only a few solitary melaleuca trees remain scattered amidst a sprawling flooded region. Concurrently, another 400 hectares are at risk of further decline if timely interventions are not made.

Mr. Le Thanh Dung, Deputy Director of U Minh Ha National Park, stated that the primary drivers behind the current forest degradation include aging trees, altered hydrological regimes, peat layer depletion, climate change, and forest fires, which cause ecological imbalances and threaten to transform the area into an alternative ecosystem type. This situation is heavily concentrated in Sub-zone 1 and Sub-zone 4 within the strictly protected sub-zone, where flooding typically lasts more than 6 months each year.

Previously, U Minh Ha National Park reported the severe degradation of the melaleuca forest to the Ca Mau Provincial People's Committee and recommended inviting leading experts and scientists to evaluate the causes and assist the locality in drafting forest restoration plans.

Recognizing that correctly identifying the causes and deploying appropriate management solutions are urgent requirements to ensure the long-term conservation of this unique melaleuca forest ecosystem, since 2025, U Minh Ha National Park has partnered with the Silviculture Research Institute of Southern Vietnam to conduct surveys, assess the causes of degradation, and propose remedial measures.

Dr. Kieu Tuan Dat, Director of the Silviculture Research Institute of Southern Vietnam, observed: “Aside from old-growth melaleuca forests that are completely dead or have over 70% mortality, thousands of other hectares of melaleuca forest are experiencing declining vitality, sparse canopy density, and low natural regeneration capacity. Extensive tree deaths and blowdowns impair ecological functions, bringing risks of structural changes to the vegetation carpet and the formation of natural grassy savannas if left unmanaged.”

The phenomenon of melaleuca mortality is concentrated in old-growth forest compartments on peatland where hydrological regimes experience prolonged fluctuations. The multi-year practice of deep water storage over long periods to prevent forest fires has led to peat layer depletion, prolonged soil anoxia, reduced soil oxygen levels, low pH, and the buildup of high concentrations of toxins such as: H₂S, CH₄, Fe2+, Al3+, SO42-. This negatively impacts root systems, hampering nutrient absorption, diminishing the vitality of melaleuca trees, and reducing natural regeneration capacity.

Furthermore, the overgrowth of vines, ferns, and choai (Stenochlaena palustris), with infestation rates ranging from 21.8% to 45%, smothers the melaleuca trees, restricting photosynthesis, halting growth momentum, and making them highly vulnerable to toppling during storms. Vines clinging to the trunks restrict the development of the trees and load added weight onto a weak substrate, making the melaleuca forest prone to swaying, root loosening, and blowing down, thereby threatening the entire canopy layer.

“A number of old-growth melaleuca forest areas have reached their natural maturity, leaving the trees depleted with poor resilience against adverse elements. When encountering compounding impacts such as prolonged waterlogging, undergrowth encroachment, pests, and extreme weather, the forest trees undergo severe degradation, resulting in mass mortalities,” Dr. Kieu Tuan Dat emphasized.

The Silviculture Research Institute of Southern Vietnam has initially proposed an integrated set of measures, including: regulating water balance to allow the forest floor a minimum dry period of 3 months per year, controlling invasive undergrowth, zoning to promote natural regeneration, and replanting within the ecological restoration sub-zone. Over the long term, intensive scientific research is required to step-by-step restore and conserve this specialized melaleuca forest and peatland ecosystem.

The Chairman of the Ca Mau Provincial People's Committee has assigned U Minh Ha National Park to chair and coordinate alongside research groups to manage and monitor all activities. The provincial Department of Agriculture and Environment will continue to guide the finalization of legal procedures, ensuring that the research aligns with conservation goals and practical conditions. The scientific community will survey the current status of the melaleuca forest, gathering data on soil, water, microorganisms, and ecosystem health to propose restoration solutions rooted in biodiversity resources.

"The current state of the melaleuca forest at U Minh Ha National Park is severely degraded, requiring integrated management practices, rational water regulation, undergrowth encroachment control, and intensive scientific research to restore the forest ecosystem and elevate forest quality," Dr. Kieu Tuan Dat concluded.